High-performance asymmetric supercapacitor based on graphene-supported iron oxide and manganese sulfide

Energy density and power density are two key parameters of the supercapacitor. Selecting suitable positive electrode materials and negative electrode materials to construct asymmetric supercapacitor is an effective way to improve energy density. Here, a novel asymmetric supercapacitor was assembled by using alpha-Fe2O3/rGO nanocomposites as negative electrode and alpha-MnS/rGO nanocomposites as positive electrode. The fabricated alpha-MnS/rGO//alpha-Fe2O3/rGO asymmetric supercapacitors (ASCs) showed a largest potential window of 1.6 V when 3 M KOH was used as electrolyte. The ASCs displayed a maximum specific capacitance of 161.7 F g(-1) at a current density of 1 A g(-1), and the highest energy density of 57.5 Wh kg(-1) at the power density of 800 W kg(-1). These encouraging performances of the alpha-MnS/rGO//alpha-Fe2O3/rGO ASCs shed light on the use of alpha-Fe2O3/rGO nanocomposites and alpha-MnS/rGO nanocomposites as promising candidate materials for asymmetric supercapacitor applications.